M300 has, according to reviews, more "air" but Ref1000 is more focused/coherent. S300 is 2x M300 since each module (200ASC) inside has its own power supply (common power connector). If you want separate cases get Rowland 102 (same modules in solid billet of aluminum with two milled out pockets).
I would go with Rowland 102 ($1.5k + 5 years warranty) and that's what I have but new Ref1000 mkII supposed to be an improvement over first generation. It is also 80% louder than M300/S300/Rowland102 and can drive lower min. load impedance (2 Ohm vs. 3 Ohm).
I would go with Rowland 102 ($1.5k + 5 years warranty) and that's what I have but new Ref1000 mkII supposed to be an improvement over first generation. It is also 80% louder than M300/S300/Rowland102 and can drive lower min. load impedance (2 Ohm vs. 3 Ohm).